DIBt Check

NEWS: How durable are TUBOGEL ® - flood rehabilitations?
In recent years a lot of discussion has developed in some places about the durability of flood rehabilitation.

It is talked about “disillusioning results” and “disappointments” in the repeat check-ups of rehabilitations with the “flooding process”.

At this point we, as the leading contractor in the field of flooding, do not want to enter into this discussion since we believe that the negative statements have often been made under conditions which would not withstand a scientific examination.
A study, performed while applying for our second building permit Z-42.3-369 for gas stations, withstands an examination at any time.
The special “charm” of this examination is the fact , that not only publicly appopinted and sworn experts but also an expert commission of DIBt with experts like Dipl.Ing. Hoppe, Dr.-Ing. Stagge or Prof.Dr. Selle have supervised the correct implementation.


So it should be undisputed, that the results of this study were reached and reproduced under absolutely perfect conditions. Since the result of the “DIBt-examination” differs drastically from the mentioned publications we have summarized the details about this subject in a short statement.

Durability of TUBOGEL® - Flood Rehabilitation proved!
One of the most important factors when evaluating flooding processes is without doubt the question: “How durable is this at all?” An examination with the participation of the German Institute for construction technique (DIBt – Deutsches Institut für Bautechnik) has now proved the durability of the TUBOGEL® flooding process by investigating gas stations which have been flood rehabilitated with TUBOGEL®.

9 out of 10 examined stations were still tight after years – 1 rehabilitation was destroyed – construction work had damaged the sealing package.

It is not easy to obtain a building permit: dozens of evidents have to be carried out, laboratory tests have to be done and certificates have to be obtained. The situation is even worse if a permit is applied for the first time for a specific area and the examination programs are not yet established but have to be worked out. That was the case when TUBOGEL® applied for the permit for gas stations: apart from the “normal” examinations of function, strength of the sealing cover, environmental safety etc. the durability of the rehabilitations with TUBOGEL® had to be proved according to the ideas of DIBt.

But how? First elaborate laboratory experiments with simulated application of loads, shear forces, dynamic forces etc. were discussed – and rejected. Finally one agreed on a simple as well as effective verification: 10 gas stations which had been rehabilitated with TUBOGEL® quite a while ago, should be given a new leak test to determine “in-situ” whether the rehabilitation was still effective after years.

A list of 600 gas stations was given to DIBt, and the people from Berlin choose 10 gas stations all over Germany. At the same time DIBt named one member of its expert committee for each project who should accompany the examinations to ensure that everything runs properly. Therefore, Mrs. Sedehizde (BWB) and Mr. Hoppe (Public Sewage, Hamburg), Dr.-Ing. Stagge (MPA Darmstadt) and Prof.Dr.-Ing. Selle (MFPA Leipzig) had the up till then unique opportunity to take part in these repeat tests together with a publicly appointed and sworn expert.

Welcome result of the action: 9 out of 10 tested stations were still in perfect condition and gave no reason for complaint.

Only at one gas station in Heidelberg the result of the leak test was extremely bad – according to DIN 1610 part W with water virtually no pressure could be built up! When consulting the owner of the station the reason became evident:

Several months ago the road surface had been renewed and the vibrating unit used obviously had destroyed the seal package.

Summary of the test initiated by DIBt:
As long as the rehabilitated pipes are not attacked with “heavy equipment”, the durability of TUBOGEL® -rehabilitation system is proved!

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